increasing speed

[kid bow]

Would thinning the width and thickness increase speed a good amount

[RBLusthaus]

All other things being equal, yes, thinning will make the bow shoot faster - as long as you dont thin them too much so that they collapse or twist off the center line. 

Russ

[Joec123able]

I would narrow those tips wayyyy down and thin them alittle should be noticeably faster after that

[Danzn Bar]

for what its worth..........I think thinning the tips is suspect as far as speed, design may have more to do with speed,  but it will defiantly help hand shock.  But that is just my short experience.  I've shot just a few of my bows through a crony.  I seam to like comfort and hard hitting arrows more than speed.  Sorry for getting off the subject , your question was about speed, 
DBar

[Pappy]

Depending on what you call a good amout,few feet a second,probably,make it a rocket,nope. Probably like DBar said,help with hand shock and may be a little sweeter to shoot.
   Pappy

[Buckeye Guy]

Lighter weight arrows will shoot faster from it !

[kid bow]

How do these look I added a double nock to raise weight a little

[Pat B]

Wood is 8 times stronger in thickness than it is in width. I'd narrow the tips considerable( 6" to 8" back from the tips). That will decraese the tip weight and give you some more speed and less chance of handshock.