My 3/4 " thru hull is 90 degree also but I will take a good look & see if a 1 1/8" straight fitting will clear the protruding threaded tip of the stern lift eye inside the transom compartment & the legs/bolts of the new GEM lift-up cleats I just installed .
Having said that there is a pretty good strong flow out of the existing set up with the 3/4" 90 degree but I would imagine it will be a lot better with straight 1 1/8" fittings.

I run 2 pumps both with float switches. One is an 800 ghp (hot to float, manual on-off connected to my starting batt. The other is a 1200gph with the float switch mounted half way up the stringer connected hot to my house battery.

Would two 2000 gph pumps be overkill for an 18Sf ? I'm thinking that smaller boats go down faster than bigger boats because of water volume to size ratio & thought the quicker the water is pumped out , the better. Someone also stated that the general rule is for every foot of boat lenght you should be able to pump 100gph.

guarantee you you'll have more gph per foot than anybody. but run'em regularly just to know they work.
do a search to check out mitchman's viddy to see how fast they can go down.

Does anyone have any experience with Ultra pump switches from USS (Ultra Safety Systems) ? The owner/developer of the switches is very helpful with info/advice , seems very confident in his product & offers a lifetime warranty. Not cheap but money well spent if they are as reliable & dependable as he claims they are.

Sidelock,
I have the USS Ultra switch in my 23'. Very robust constuction; has been in my bilge for approx. 9 years now with no issues. Highly recommended.