You have two different abilities that can overlap if used correctly.
First, the Rakshasa Bloodline's bloodline arcana, allows you to decide which spell it is "identified" as regardless of the type and school of the spell you just cast, with the benefit of also increasing the DC to identify your spells. So, this ability has a broader utility and can be applied to all spells you cast, they simply have to fail their checks.
Second, the Stylized Spell metamagic feat allows you to increase the DC on demand, by increasing the slot used to cast the spell by 1 and make the spell to be identified as another from the same school, subschool and descriptors, unless they pass the normal check's DC by 10. It also increases the DC to identify the magical aura or signature using Knowledge checks by 10 (which is not something easy to come by).
You also may adjust the total DC by minus 5 (for a total of +5 instead of +10) to modify other parts of the spell, such as the descriptor (allowing a [fire] spell to look like a [cold] spell), the school and subschool (making a necromancy spell appear to be a conjuration spell), the spell's source of magic (make an arcane spell appear to be a divine spell), the spell's origin (make it looks like that fireball came from behind that rock over there), imitate another stylized spell, suppress audible or visual effects (make it look like you didn't cast any spell at all). You get to pick one of those extra effects when you decide to reduce the DC like this.
Finally, the stylized spell also gains the ruse descriptor:
Ruse: The “ruse” descriptor applies to spells that appear to be other, usually more harmless spells in order for the caster to fool her opponents. Spells with the ruse descriptor are easily mistaken for other spells and are intended to confuse even onlookers trained in Spellcraft or Knowledge (arcana). Attempts to identify a ruse spell by its effects, its aura, its components, or other attributes with a skill check treat the spell as though it were a different spell, as indicated in the spell’s description. The one attempting the check can correctly identify the spell only by exceeding the DC by 10. The false spell is typically a level lower than the ruse spell, so skill checks use the DC for the lower-level spell. Even detect magic and most similar spells don’t prevent the caster from being fooled by a ruse spell. Analyze dweomer, greater arcane sight, and similar spells of the same or higher spell level that automatically identify spells reveal a ruse spell for what it is. Ruse spells that mimic harmless spells still list harmless on their saving throw or spell resistance lines; a creature that knows or suspects the true nature of the spell typically chooses to attempt the save.
The result of applying both is that first the DC to identify all your spells is increased by 1/2 your sorcerer level, and any checks that fail by 5 or more against this DC will be identified against any spell you want. Say you are a 6th-level sorcerer casting Invisibility (2nd level spell) and has +5 cha bonus, the DC to identify spells is 10+spell level+cha bonus. So, normally that would be a DC 17, but since you have the arcana bloodline, this DC is increased to 20. This is the normal DC for all spells you cast. If they fail that check by 5 or more (like rolling a 15), they could identify that as a Dimension Door (4th), or as a Teleport (5th), or even a Gate (9th). Really, this ability doesn't care how you are masking your spell effects, if they fail, they identify it as something completely different that you can come up with that will make a decent ruse (no pun intended).
Then, you may decide to increase the spell level by 1, using a higher spell slot (3rd instead of 2nd) and cast your stylized invisibility. This would increase the normal spell DC by 10, for a total of DC 30, and not only fool Spellcraft attempts to identify the spell as it is being cast, but also fool Knowledge(Arcana attempts to identify the lingering effects (see Detect Magic), but it also has to look like another Illusion (glamer), like Blur. The Spellcraft DC to identify this correctly as invisibility will be 30 (yep, that high). While simply failing the check will cause them to identify it as blur instead of invisibility, failing the check by 5 or more will cause them to identify the spell as any spell you want (because of the bloodline arcana). If they fail the check by 10 or more you also get to choose if they identify anything at all.
If you decide to increase the DC only by +5 when using the stylized spell, you can apply one of the other effects, for a total of DC 25, but you get to play a little more with what kind of spell they may incorrectly identify it as.