I've done this trip VFR quite a few times.
The cloudbase over the sea is often higher, or even CAVOK, when the land is murky. 5000' (or FL 50) is often VFR and seems OK with Dublin while east of Killiney (KLY). (Remember it is controlled airspace all the way from the FIR boundary to Weston). I think there is an airway at 6000 on the UK side (don't have chart here) so watch that. The higher the better.
There are reporting points like LIFFEY and KUSIT that are not on the UK VFR chart but are worth marking in and using when reporting the boundary.
Make sure you have the Valley frequency which is not as shown on some older! charts as they are very helpful. Also London Information can be hard to raise on 124.75 in this sector but the frequency shown on the N England chart does work.
You may get a danger area crossing from Aberporth sometimes even if it's 'hot' (For instance I did Arklow - Caernarvon direct on one occasion) so it's worth asking.
The Weston circuit is very cramped but the airfield has improved no end recently and they now have a tower with A/G (dont know the exact status but it is a big improvement because they can see you inbound now). They have a coffee shop, hard parking and can get you taxi or car hire.
When you land at Weston rwy 07 be prepared to taxi to the end where there is a refuge and await landing traffic before backtracking. I suggest not to cross the grass to the parallel taxiway, at this time of year anyway.
The IAA have a useful document on Weston at
http://www.iaa.ie/ (you have register, then type 'Weston' into the search).
Dublin hand you off when you are visual with Weston which can be difficult to spot. They will also close your flight plan but do request this on the radio before changing.
You are looking for a narrow runway 25/07 about a mile S of the river with a lake and a large industrial unit to the W. I've been there many times and still find it hard to see. They might ask you to join overhead at 1500' but Dublin starts at 1500'! so 1450' is about right.
Be prepared for Dublin to route you north and west around the zone via Gormanston (now inactive) and Navan if the weather is not VFR and into / out of Weston along the canal.
On the UK side the weather is often murky east of Valley and there is a lot to be said for the low level route along the N Wales coast to Point of Air remaining clear of Liverpool and south via Hawarden Shawbury Wolverhampton etc all of whom are helpful and make good diversion options. You can do the whole trip at 1500' if neccessary.
Sorry it's a long post but hope it helps.