Hi Ken,
What E/Ps. do you have now? If you have E/Ps ranging from 6mm say to 25mm in 1.25inch, then a Barlow will double your mags.
A personal comment if I may, I use a few Meade E/Ps with my 10" f4.5 DOB. They are series 4000 Super plossls. I have the 6.4/9.7/12.4/15/32mm and #140 Barlow + S4000 Ultra Wide Angle 14mm.(1.25+2"), along with an 18+25MA. They give crisp images but are a bit pricey at about $140 ea.(NOT the UWA,near$700)!
A few of our members have the Andrew's range of E/Ps. and are very happy with them. There's not a lot of diff. in image quality.
If you want low mag with a reasonable fov, then go with the 30mm Superview 68 degree E/P.(50x@.44degree). I'm not sure about the 42mm SV68. You might get some vignetting, due to it being an f5 t'scope.
Your best bet is to TRY/BORROW a 42mm E/P and see if it's O.K. before you buy.
Why not go for a 12 or 15mm SV 68 if avail.?Cost???
HTH.